MMP9 and COVID-19: These findings have potential implications in COPD35,36 and pulmonary fibrosis.37,38 In addition, several proteases related to angiogenesis were downregulated including EGF-like protein 7 (EGFL7), chordin like 1 (CHRDL1), C-type lectin domain containing 14A (CLEC14A), plexin domain containing 2 (PLXDC2), MMP9, and CTSL, which is consistent with the results indicating repressed angiogenesis in the COVID-19 lungs (Fig. 2).